Initial firing and run-in plan.
Looks like I'll finally be ready to fire it up on Saturday. I was pushing pretty fast, and then decided to slow down a bit and make sure I've got things dialed in. I spent some time researching an initial firing and run-in protocol, found a few good descriptions from pro builders, but they gloss over some details and special cases. And I'm definitely a special case. If something can go wrong, it will go wrong when I do it, so I try to figure that stuff out in advance and hedge against it.
Luckily I was able to get some input from the guys on Lextreme and from Kelford to come up with a super-duper driveway-mechanic idiots guide to running in a new engine that you can't afford to blow up. Here are the details I put together for my run in based on input so far. Feedback welcome.
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1. Fill the motor with non-synthetic break-in oil. Nick at Yota1 got me some break-in oil with extra added zinc, which helps with the initial break-in. Install a new fuel filter. I put in a new radiator and all new hoses--small comparable investment compared to the engine. Double, triple, quadruple check all hoses and wire connections. Make sure your battery is fully charged so you get a good crank.
2. 2uz motors are not easy to prime with oil, and the oil pumps are apparently not known for self-priming. You could just fire it and hope for the best, but if the start is labored and you have high-end cams, you could wind up grinding surfaces as the assembly lube wears off if there's no oil pressure. Not good. The solution is a bit of a pain, but again, small relative investment.
Disconnect the fuel lines so it can crank without firing, and remove all the spark plugs. That will eliminate compression and allow a much faster initial crank, which is what you want for the cams, and it will allow you to get oil moving while making sure you're generating oil pressure. Then remove the valve covers so you can see the cams. Put some oil in a squirt bottle and oil the lobes of the cams just before you crank it. Now you're ready to give it a good crank so you can see if you're getting oil pressure, and you won't grind the cams against the valve tappets. If you crank it and you get pressure (use a manual pressure gauge or an OBD2 monitor), you're good to go. Oil the cam lobes again, then put the valve covers on, install the spark plugs, and connect the fuel lines.
3. Now that you know you have oil pressure and the cams are happy, you can fire it up. Leave the radiator cap open until the engine gets to temperature and the thermostat opens, so the air purges from the system. You want a quick start, not a lot of cranking, so if it doesn't fire up, move to troubleshooting. Don't keep cranking hoping it will catch.
4. If it starts right up, the idea is to run it for 20 minutes at operating temperature, but not at idle. You want to vary the RPMs steadily in the low to low-mid range. Don't wind it up to redline, just keep varying it for several seconds at different low-mid levels. Ideally you can have someone do the throttle while you check for leaks--particularly coolant or oil. Keep an eye on oil pressure.
5. If you also rebuilt an automatic transmission, like I did, there's some added fun. The tranny doesn't take all the fluid it needs on the initial fill. You have to run it through the gears to get fluid flowing through the whole system, and add fluid as it's needed. That's a bit of a trick while you're simultaneously running in the engine. I left my drive shafts disconnected so I can have my throttle person shift through the gears without driving off. I also put a quart of fluid in the torque converter before I started it so it's not dry. I've got a tube installed into the filler hole, and quarts ready to add as we go. The plan is to do one gear at a time, add some fluid, go to the next gear, add some fluid, and slowly bring it up to the manufacturer specified capacity.
6. Once the motor has been running at operating temperature and varying RPMs for 20-30 minutes, shut it down. Let it cool only enough to be able to drain the oil, but don't wait too long--you want the oil to be viscous enough to fully drain. Drain it into a pan--hopefully no obvious metal shavings come out. Replace the oil filter--some people even suggest cutting it open to look for signs of metal caught in the filter. Not sure I'd want to know at that point. Fill the motor back up with another round of break-in oil with zinc. Check all your fluids again.
7. The next step is a road run-in. You don't want to put any heavy load on the motor for at least 500 miles--no big hills, no towing or hauling. This is where it gets a little controversial on the boards if you search for run-in procedures. Some people swear by winding up the motor hard. I'm siding with the crowd that suggests a more measured run in. Find someplace flat where you can safely drive between 30 and 60 mph, and start doing intervals. Roll at 30mph, then bring it up to 60 for several seconds and drop it to 30, repeat 6-10 times. This is about seating the rings properly. My crude understanding of it is that when you let off the gas at 60 and the motor is spinning down, you're basically polishing the cylinders. I probably have the mechanics of that wrong, but the procedure is widely recommended just after you do the first firing up.
8. After the road run-in, drive it normally for 500 miles--again, no towing, no big loads, etc--then change the oil and filter. During this period, I'm planning to try to smog it. And when the 500 miles is up, I'll take it up to Sac to get the ECU installed, tuned and dyno'd.
So, that's my super duper idiot's guide to running in a new motor. Probably more anal than your mechanic would recommend. But, if you've spent more than $10k and months building a motor, and you have the kind of luck I do, you might want to spend the extra effort.
Like I said, feedback is welcome. I compiled this from a lot of other people's input, and I'm sure I might have missed something or got something wrong.
